Trocar



W. B. WESCOTT.

TROCAR.

, APPLICATION FILED AUG-4, i919.

, 1,333,745. Patented M31-\16,19 20.f

- mvsnron.

ATTORNEYS v v 5 UNITED STATES PATENT OFFICE.

WILLIAM BURTON WESCOTT, 0E WELLESLEY, MASSACHUSETTS, ASSIGNOR TO KALMUS, COMSTOCK -& WESCOTT, INQ, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

To all whom. it may concern:

Be it known that 1, WILLIAM BURTON Wnsco'r'r, a citizen of the United States and resident of VVellesley, -in.the county of or- .folk and State of Massachusetts, have invented new and useful Improvements in Trocars, of which the following is a specification,

This invention relates to a trocar for collecting blood from animals at. the time of slaughter and consists in certain modifications of and improvements upon instruments of the character shown in my applications for Letters 'Pa-tent of the United States, Serial Nos. 288,641, filed April 8 1919, and 304,317, filed June 14, 1919, particularlyin respect to the perforator or blade at the forward end of the cannula.

In the accompanying drawings which illustrate certain embodiments of the invention,- i l .1

Figure 1 is a side elevation, partly in section, of the forward end of the trocar;

Fig. 2 is a longitudinal central section taken at right angles to the plane of Fig. 1; Fig. 3 is a top plan or end view;

Fig. at is a side elevation partly in. section, of the forward end of a modification Fig. 5' is a longitudinal central section taken at right angles to the plane of Fig. 4:;

Fig. 6 is .a top plan or end view of said modification;

Fig. 7 is a side elevation of'another modification of the invention;

Fig. 8 is a top plan or end view of the modification shown in Fig. 7 and Fig. 9 is a section line 9-9 of Fig. 7.

Referring first to the form shown in Figs. 1. 2 and 3, the tube or cannula is indicated at 11 This may beof any suitable and convenient length and may be provided with means for retaining the instrument in the wound such as shown in either of my aforesaid applications.

2 is an elongate perforator blade having a sharp tapered. point and two sharp cutting edges. The blade 2 is carried by an annular member or collar 3. with which it may be made integrah or to which it may be otherwise fixed.

The annular men'lber 3 is removably S81 cured to the forward end of the cannula 1.)

,TROCAR.

Specification of Letters Patent. Patented Min, 16, 1920.

..-'-'Application filed August 4,

1919. Serial No. 315,187.

ually merge into the sides of the blade 2 at each side of the aperture 5,formed. through the base of the blade 2. The walls #1 serve to spread open the cut made by the blade and facilitate the entrance of the cannula into the cut, also to hold the walls of the cut from closing over the entrance into the cannula and preventing the free flow ofv blood therethrough, and alsoto brace 'and strengthen the blade where it is most weakened in the region of the aperture 5. The walls 4 form in effect continuations of the walls of the cannula.

It often happens when the instrument is inserted in the wound of the animal from which the blood is to be drawn that the.

blood pressure is wholly or mainly at one side of the blade in which case the effective opening into the cannula would be limited to the area of the cannula entrance atthe pressure side of the blade if it were o of such size that combined with the area of the cannula. entrance at either side of the blade its area is substantially as great as or greater thanthe total areaof the cannula entrance, the effective opening into the cannula is substantially equal to the cross sectional area of the cannula notwithstanding the'fiow of blood is wholly, or mainly at one side of the blade. When the blade is disposed diametrically of the cannula. as in the forms shown-in Figs. 1 to the area of the aperture '5 should be substantially equal to half the area of the cannula entrance.

The upper or outer edge of aperture 5 is preferably beveled or sharpened as indicated at 6 to prevent the same from catching in the walls of the cut when the instrument is withdrawn.

The annular member 3 has a shoulder 7 fitting over the end of the cannula to form th"erewith a smooth continuous surface; and

.pxtend into the bore of the cannula, and

and has forwardl tapering walls 4, the "have projections 9 which snap into correcdgcs of which converge toward and gradspouding sockets in the walls of the cannula, thus rigidly but. removably holding inserted into the animal throughthe hide without previously cutting a slit preparatory to inserting the trocar. "The hide is so tough and inelastic that the. instrument L shown 1 to 3 could be inserted through the hide only With the greatest dithculty without first opening a slit large enough to receive the cannula." The blade shown in F ig. 4 however Willform'its own slit.

which spread the wound and reinforce the blade, flare laterally to conform to the shape and Width of the'blade. Inother respects the parts are substantially similar to those of the form first describe In the modification shown in Figs. 7 8 and 9- the perforator blade is formed of .three parts 2", 2 and 2 arranged angularly and radially with respect to the axis of the cannula,"thus making a cut or incision of three diverging lines, capable of ,being spread open to form a wound a'pproXi-' mately equal to the circumference of the cannula. This form ofinstrument, like that 5shown in Figs. l, 5 and 6, may be used to make its own "incision through the hide Without previously slitting the hide to admit the cannula. The edges of the blades in .this form need not extend beyond the petO, riphery oft-the cannula. The aperture 5" is made through all three parts of the blade for the purpose already explained in connection with the aperture 5, and the tapering walls 4:", corresponding to the tapering walls a, are

provided for each of the three parts.

other respects the construction of this form is substantially the same as already described with reference to the other forms.

.Iclaim:

50, 1. A trocar con iprising a cannulmand a 'perforator blade secured to the forward end of the cannula, said blade having an aperture through its base adapted to permit the -fioyv of blood from .one side of the blade through the aperture to the opposite side of .the cannulaentrance. e

2. A trocar comprising a cannula, and a perforator blade secured to the forward end of the cannula, said bladehaving an aperture through its base adapted to permit 3 the flow of blood from "either side of 'the blade through the aperture to the opposite SldQrQf the cannula entrance. V

With this. 10 form of instrument the perforator may be In this form the tapering walls e,

area to half the area of the cannula entrance adapted to permit the flow of blood from either side of the blade through the aperture to the opposite side of the cannula entrance. v

l. A trocar comprising a cannula, and a perforator blade seemed to the forward end of the cannula, said blade having an aperture through its base adapted to permit the flow of blood from either side of the blade through the aperture to the opposite side of the cannula entrance, the area of said aperture combined with the area of the cannula entrance at one side of the blade being sub-' stantially as great as the total area of the cannula entrance.

5. A trocar comprising a cannula, a per-' forator blade having an aperture at its base, and an annularmember carrying the perforator, said annular member having forwa'rdly tapering walls merging into the blade at the sides of the aperture.

6. A trocar comprising a cannula, a perforator blade having an aperture at its base, an annular member carrying the perforator, and means to secure the annular member to the end of the cannula, said annular. member havil'ig forvariilly tapering Walls merging into the blade at the sides of the aperture.

7. A trocar comprising a cannula, a perforator blade having an aperture at its base secured to the end of the cannula, and forwardly tapering Walls at the end of the cannula merging into the blade at the sides of -the aperture.

8. A. trocar .con'iprising a cannula, aperforator blade secured to the end of the cannula, and forwardly tapering Walls at the end of the cannula merging intothe sides Of\ the blade.

9. A trocar comprising a cannula, and a perforator blade secured to'the forward end of the cannula, the cannula entrance'being open at each side of the blade,.and the perforator blade being adapted to makelaij incision approximately equal, when spread open, to the circumference of the cannula.

10. A'trocar comprising a cannula, and a perforat'or blade SQClll'm. to the forward end of the cannula, said blade being wider than the diameter of the cannula to form an incision approxinnrtely equal, when spread open, to'the circumference of thecannula, and' tho cannula entrance being open at each side of the blade.

Signed by me at'Boston, -Mass., this 29th day of July 1919.

' j WILLIAM BURTON VESCOTT. 

